Statistical Confirmation of a Stellar Upper Mass Limit

We derive the expectation value for the maximum stellar mass (mmax) in an ensemble of N stars, as a function of the IMF upper-mass cutoff (mup) and N . We statistically demonstrate that the upper IMF of the local massive star census observed thus far in the Milky Way and Magellanic Clouds clearly exhibits a universal upper mass cutoff around 120− 200 M⊙ for a Salpeter IMF, although the result is more ambiguous for a steeper IMF. Subject headings: stars: early-type — stars: fundamental parameters — stars: mass function — stars: statistics — open clusters and associations — galaxies: stellar content